The present invention generally relates to body fluid sampling devices, and more specifically, but not exclusively, concerns a disposable lancet and lancing cap sampling device and a technique for sampling fluid with the device.
The acquisition and testing of bodily fluids is useful for many purposes, and continues to grow in importance for use in medical diagnosis and treatment, and in other diverse applications. In the medical field, it is desirable for lay operators to perform tests routinely, quickly and reproducibly outside of a laboratory setting, with rapid results. Testing can be performed on various bodily fluids, and for certain applications is particularly related to the testing of blood and/or interstitial fluid. Such fluids can be tested for a variety of characteristics of the fluid, or analytes contained in the fluid, in order to identify a medical condition, determine therapeutic responses, assess the progress of treatment, and the like.
For example, a common medical test is the measurement of blood glucose levels for diabetes. Diabetics must test their blood glucose levels several times a day. The glucose level can be determined directly by the analysis of a blood sample, or indirectly by analysis of other fluids, such as interstitial fluid. Other medical tests may analyze a body fluid sample for a variety of properties or components, as is well known in the art. For example, such analysis may be directed to hematocrit, cholesterol, uric acid, coagulation, etc.
The testing of bodily fluids basically involves the steps of obtaining the fluid sample, transferring the sample to a test device, conducting a test on the fluid sample, and displaying the results. These steps are generally performed by a plurality of separate instruments or devices.
In one form, a body fluid sampling device is composed of a lancet to form an incision and a microcollection tube to collect the body fluid. However, the lancing and collection are two separate activities requiring hand coordination and dexterity to perform both activities. Often this is difficult for those persons that are elderly or young.
Another form of collecting a body fluid sample is with a suction-type blood sampler. This device develops suction between a lancing site and the end of the device when the lancet holding mechanism withdraws after piercing the skin. A flexible gasket around the end of the device helps seal the end around the puncture site while the user attempts to draw a sample from the puncture site or the user pulls back on the device to release the seal. A diaphragm over the puncture site can also create a vacuum. This type of device only draws bodily fluid while the device creates a vacuum with the skin to form suction pressure. However, after the air is expelled, the suction pressure will cease and no additional body fluid is collected.
An alternative form of collecting and measuring body fluids uses a coaxial syringe and capillary tube disposed within a spacer member. The spacer member limits the depth of syringe penetration, and compresses body tissue around the syringe while the syringe is in the skin, for improving the flow of interstitial fluid to the incision. However, it will be appreciated that the incision will tend to close against the syringe, thereby limiting any advantage that can be achieved.
One problem associated with some lancing devices that control or adjust the puncture depth to reduce the pain of lancing is that the blood lancet device does not collect blood from the incision.
Some forms of a disposable lancing device include a plastic injection device that may be alternatively used as a syringe-type injection device and a lancing device with a disposable solid needle lancet, depending on configuration. However, this type of device does not collect a body fluid sample.
One problem associated with some lancing devices is that the devices must be cleansed to maintain proper hygiene between uses of the instruments, and to prevent cross-contamination and/or contamination. Cross-contamination of blood samples may be a problem if more than one person uses the devices and the devices are not properly cleansed between each use. Contamination of a blood sample may be a problem if one person repeatedly uses the devices without properly cleaning the devices between each use.
In institutional settings, the bodily fluid sample is often collected from the patient and then introduced to a test device in a controlled fashion. Some blood glucose monitoring systems, for example, require that the bodily fluid sample be applied to a test disposable that is in contact with a test instrument. In such situations, bringing an incised finger or other incised body part of a patient directly to the test disposable poses some risk of contamination from bodily fluid of a previous patient. With such systems, particularly in hospital settings, a patient is lanced, a sample is collected in a micropipette via capillary action and then the sample is delivered from the pipette to the test disposable. However, this technique still produces hygiene and cross-contamination problems, and is inconvenient because it requires the use and disposal of three components, the test disposable, the lancet, and the blood collection device.
Another problem associated with some lancing devices is that fingertips are commonly lanced to obtain an adequate sample of blood and repeated lancing of fingertips can be painful due to the high concentration of nerve endings in the fingertips. Therefore, alternate sites on the body that have fewer nerve endings may provide a less painful area to sample blood or other body fluids. However, these alternate sites may produce less body fluid when lanced as compared to fingertips. Therefore, it is important to reduce the amount of fluid required for testing at an alternate site. To adequately test body fluid obtained from an alternate site, enough fluid must be expressed and collected from the incision before the fluid can be tested.
Yet another problem associated with some lancing devices and testing devices is that such devices are disposed of independently thereby creating additional hazardous waste.
Thus, there remains a need for improvement in this field.